Pump



March Z0, 1951 E. ORSHANSKY, JR n PUMP 8 Sheets-Sheet 1 Original- FiledJuly 18, 1947 March 20, 1951 E. oRsHANsKY, JR 2,545,929 l PUMP l 8Sheets-Sheet 2 Original Filed Jul;r 18,y 1947 INVENTUR /'lz'as rsansg,f1:

March 20, 1951 E. oRsHANsKY, JR 2,545,929

PUMP

Original Filed July 18, 1947 8 Sheets-Sheet 5 VIII/,IL

lll/IIL flu lll/III] i IIN@ me #im March 20, 1951 E. oRsHANsKY, JR2,545,929.

PUMP

Original Filed July 18, 1947 8 Sheets-Sheet 4 March 20, 1951 E,ORSHANSKY, JR 2,545,929

PUMP d OriginalFiled July 18, 194'? 8 'Sheets-Sheet 5 www March 20, 1951l E; oRsHANsKY, JR 2,545,929

PUMP

Original Filed July 18, 1947 8 Sheets-Shet FROM SUPP! Y UNDER PPE T0ll/N i INVENTOR. 'as @dd/:slak BY M w/ March 20, 1951 E. oRsHANsKY, .IIR

PUMP

` 8 Sheets-Sheet 7 Original Filed July 18, 1947 INVENToR. z/z'asrsdns/y, fr." BYM( w "in E. ORSHANSKY, JR

March 20, 1951 PUMP 8 Sheets-Sheet 8 maw m H .1.9 md n f.-

.I )K mm Wr Il m L a Sw www W. N T it www, N Mmm im, ,VNJ UTET A@ w ,wNw fr ...H--- Q is .i L wl .MN .1 -1\. ww H {HIIUL l II 1| I d f f f IPatented Mar. 20, 1951 PUMP Elias: Grsha'nsky; 11i.; Stamford, Conn.,assigner to ThefAcrotorque Company, Stamford, Conn., a corporaticnof.Connecticut ContinuationY of application SerialiNo; 761366,July-18,1947. This-application Marchl, 1949,

Serial Nor-84,5232'v 1.9 Claims. lf..

This invention re1ates:to..pumps= and especially to varialcle.- volumelpositive. :displacement pumps ofl the type: inwhichworkin'gf pistons.also per-v form the; function of valvi-ng the fluid .displaced by otherypistons.` This; applioationisl afcontinuation. ofv my z applicationSerial Number 161,866., ledfilulyrls; 11943.,

An object of this inventionzis: to. provide: apump having an' improvedconstruction and arrange.-

ment. for accomplishinggthe: required resultsV with 2 description of anillustrative embodiment. of the,` invention taken in connectionwiththe-aecomlpanying drawings in which;

Eig.. l` is. a longitudinal. sectional View vrthroughz apump'constructed in accordance with one-emi#Y bodinrent of this"invention;

Fig.12V is a transverse sectional view on the line Fig. 3 is a. sectionon the 'line' 3 3 cfg-Fig. 1;

Fig. 4 is a diagramatic: layoutv of the cylinder block andl pistons,showingzthef methodV of and arrangement for valving the cylinders;

Fig. 5. is1 a. perspective view',v with parts broken away,` lto.showf-the manner of; valvingthe: pump cylinders;

Fig. 6 is an exploded viewof certain wobble disk details.;

Fig. 7 is a longitudinal sectional view similar; to Fig.. '1, showing Lapumpof modied construction taken on line 'I-lof Flei;

Fig. v`8A is: a. transverse. cross-sectional :viewfof the constructionofFigi? taken on the 1inef8-'I of Fig-7;

Fig. A9 is: a perspective viewwith parts broken away showing the,'construction of Fig. .7 and s Fig. lo isa diagrammaticlayoutof the.cylinder block and pistons: showing. the relative positions of the.various' pistons andn their motion..

Ingeneral; the.- invention. comprises av relatively rotatable. shaft andcylinder-.blockin Vwhich axially` extending cylinders. f are arranged`ininterspersedl` pairs; They pistons in; each pair of; cylinders. haverods or. stems extending: outwardly `in opposite idirectionsr, andseparate, angularly: aci--Y justable, wobble disksare mounted forrotation by the. shaft for reciprocating the. separate groups cipistons. Each .cylinder ot.. each .pair has a. pressurevchamberf-porti`on Vand ra valve chain-ber portion. The pressureAchamf-beriof. each cylinder' in eachpair communicates Y.with pump inletfand delivery?.` manifolds through! theyalve chamber portion of theother-cylinder insthepair,` and-each piston Lhasra body portionformed.lto providea slide valvel for controlling the .valving of the adjacentcylinder. Forf properA valvling,l the piston is one of 'eachpairofcylindcrs-isdis-1 placedl from the-other o its `pair-lily a 90Pphase difference, and this is accomplished by Va suitablel angularmounting of the separate wobbledisks relative.= to eachother. l

The mechanism-by which the wobble-'disks reciprocate the pistonsis--such-that the pistons are substantially free of'sidethruston the-cylinder wallssothatscoring `:from this cause-is substantially eliminated.Volume delivery ofthe puin-p: is varied by simultaneously varying thestrokes -of' all pistons,Y andth-is- -isl accomplished by a simplemechanism for simultaneously aflj'usting the angles? of" -theseparatewobble disks relative to theaXis of the supporting shaft- Inf-thedrawings,l the-invention isillustrated asl comprising a stationarycylinder block I-I" and rotatable vpurr-1p1shaft' I2I. The `blockincludes a plurality of pairs of'- cylinder bores-I-3'-, I-4.- PistonsI5l and I are reoiprocablyrn'o1.1ritedl inl eachpair of cylinders I3,I4,.respectiv'ely, and have stemsIT--and t8 extendingoutwardly `inopposite directions.

An annular `housing 2li surrounds the cylinder blockV I IE and-isprovided with a pum-p delivery manifold 22' communicating withannular port 23,*cornmon.to-al1lI purnpcyl-inders I3- and IIL Theannular housing also has a pumpv inlet manifold- ZLcQmfm-unicatingthrough Van annular' port v25 in the cylinderl blockwith thewv'alve.chamber portions 25. of thecylinders` l3l`of each'pair, cylinder heads25 Vbeingy provided in eaclrlcylinder It for closingoit'such.cylindersrfrom the: port 255v and providing pressure-.chambers 2'IAtherein'. A second :pump inletu manifold f 28. is provided` in' theopposite side oi?A the housing ZI .and communi'cates. with the. valvechambers 2li-of cylinders I4 of each pair throughanrannul'ar port13I.inthe cylinder block. Theport .3E is closed olii from the other`cylinders, I3 of each pair by ycyl-- iirder'he'ads 322! which providepressure: chambers 33 in the. cylinders I3;V

. i 3 With reference to each pair of cylinders (see also Figs 4 and 5),the piston I5 in cylinder I3 alternately connects the inlet manifold 24and the delivery manifold 22 with the pressure chamber 21 of theadjacent cylinder I4 through a valve passage 34 connecting such pressurechamber 21 with the valve chamber portion 25' of the adjacent cylinderI3. Similarly, the piston IB in the cylinder I4 alternately connects thepressure chamber 33 in the adjacent cylinder I3 with the inlet manifold28 and the exhaust manifold 22 through a valve passage 34"V connectingthe valve chamber portion of cylinder I4 with the pressure chamber 33 ofthe adjacent cylinder I3.

The piston rods I1 on the group of pistons I5 extend outwardly in onedirection, toward the left in Fig. '1, while the rods I8 on the group ofpistons I6 extend outwardly in the opposite direction.

A wobble disk 35 is arranged to reciprocate the group of pistons I whilea second wobble disk 36 is arranged to reciprocate the other group ofpistons I5. Each wobble disk is supported on the pump shaft I2 forrotation therewith and is angularly adjustable thereon to vary thepiston stroke of the pump. Each wobble disk comprises a counter-balancedhub 31 pivotally supported on the pump shaft by a pin 38 extendingthrough the shaft and hub. An annular wobble plate 39 is clamped againsta positioning shoulder 4G on each hub 31 by a nut 4I and is arranged toreciprocate the associated group of pistons through slidable crossheadsof such construction as to substantially prevent the transmission ofside thrust to the pistons from the wobble disks. As illustrated, thismechanism includes wear members 42, 43 of partial ball shape havingtheir nat faces frictionally engaging opposite sides of the annularwobble plate 39. These wear members are so formed that their centers ofcurvature lie in the central plane of the wobble plate 39, The wearmembers are seated in cup members 44, 45, respectively, which are inturn positioned in a slotted sleeve 46 slidably mounted in a supportingcylinder 41 formed in a wobble plate housing 48 which is secured to oneside of the cylinder block II and manifold member 2I so as to enclosethe associated wobble disk and piston rods. Ihe wobble plate 4I extendsinwardly between the-wear members 42 and 43 through the slotted wall ofthe sleeve 46, the latter being in line with the associated piston rod.Each cup 44 and 45 has a ange 49 engaging the sleeve on one side of theslot and a spring plate 5i) assists in positioning and holding the c up44 in the sleeve.

The associated piston I1 is loosely connected to the sleeve 46 to permita slight radial movement therebetween. This is illustrated as formed bya snap-ring 5I mounted in a groove in the adjacent piston rod andpositioned so as to bear against an inner flange 52 in the sleeve 46 onthe outward stroke of the piston when the sleeve 5 is drawing theassociated piston outwardly. On the inward stroke of the piston the cupmember 45 bears against the end of the piston rod. A slight amount ofradial play is provided between the `piston I1 and the interior flange52 and the ring 5I is so dimensioned as to permit such radial play. As aresult, it will be apparent that substantially no lateral thrust isapplied to the piston. Such lateral thrust as results from operation 'ofthe wobble disk will be substantially entirely absorbed by thereciprocating sleeve 46 and the supporting housing 48, the engagingsurfaces of which can be easily lubricated. The prevention of lateralpressure of the pistons on the cylinder walls renders the pumpparticularly adapted for the pumping of any fluid which interferes withcylinder wall lubrication.

The housings 48 on each side of the cylinder block rotatably support thepump shaft through ball bearings 54 which are secured to the housingsand the pump shaft in any suitable manner.

As best shown in Fig. 6 each wobble disk is counterweighted to balanceboth the wobble disk itself and also the rotating moment produced byreciprocation of the pistons. Each hub 31 has spaced counterweights 55formed as part of the hub portion. A separable counterweight member 56is also mounted on the opposite face of the hub by suitable bolts 51.Both counterweights are slotted to permit angular adjustment of thewobble disk on the pump shaft.

The Volume delivery of the pump is varied by piston stroke adjustmentwhich is in turn accomplished by controlling the angles of the wobbledisks relative to the shaft axis. In the present invention adisk-adjusting sleeve 6I is slidably supported on the pump shaft I2 andconnected to each wobble' disk hub 31 by a pin 62 mounted in a pin block63 positioned in a groove 64 of the sleeve 6 I, and engaging openings inthe associated hub portion 31 on one side of the pump shaft. The sleeve6I can be moved longitudinally of the pump shaft by any suitablemechanism such, fol1 example, as a crosshead B6, mounted within thehollow pump shaft and connected to the sleeve 6I by a pin `61 extendingthrough diametrically opposite slots 68 in the shaft. A rod 69 or thelike extends outwardly from the crosshead 66 to be actuated in anydesired manner. The opposite end of the pump shaft is shown with splines1I for connection to any suitable source of power.

As heretofore pointed out, in order to provide for proper Valving of thecylinders by the associated pistons, it is necessary that the piston inone cylinder of each pair be displaced from the other piston of thatpair by a phase diiference of substantially 96. In other words, in thepresent invention, one group'of pistons, for example those in cylindersI3, lead the other group of pistons, those in cylinders I4, by a phasediiference of This is accomplished by mounting the wobble disk actuatingthe first group of pistons in such a way that the supporting pin 38extends through the pump shaft at the required angle to the pin 33supporting the other disk. In the illustrated embodiment which shows an18 cylinder pump, it will be apparent that the cylinders of each pairare 20 apart from each other, therefore the wobble disk actuating thepistons in the cylinders I3, for example, is supported on a pinpositioned at an angle of 70 to the pin supporting the other wobbledisk, as shown in Fig. l.

Rotation of the pump shaft by a suitable prime mover operates the wobbledisks to reciprocate the various pistons, the stroke depending upon theadjustment of the sleeve BI controlling the disk angle. Inward movementof a piston operating crosshead by a wobble disk causes the associatedcup member 45 to engage the adjacent end of the piston rod I1 to move itinwardly without transmitting lateral thrust to the associated pistonand cylinder wall. Reverse movement of the crosshead moves the cupmember 45 out of contact with the piston rod and causes the ange 52 ofthe slidable sleeve 45 to engage the ring 5I on the piston rod and drawthe pisamas-aa ton in the opposite direction: The' 'val-vingof eachcylinder is controlled and operated by the reciprocation of theycombined' piston-valve in the associated cylinder. The arrangement issuc-h as -to provide the necessary 90?" lead of v one piston by theother. Also,. the associated cylinders are closely adjacent to eachother, so. that the Vproper valve Vtiming is obtained withoutthenecessity of elongated valve passages. between the associatedcylinders. The angle-controlling .sleeve 6I is easily yadjusted-by therodg tovvary the; pump stroke.

The operation and Y valving. isbestz Lillustrated in thediagram of Fig..4a Iirthis. diagram each point 12' indicates/thecenter' of theballforrned by the wearmembers 42,--'43.. at. which` point thereciprocating force vof the wobble` disk is applied to the. associatedpiston in .line .withv the axis thereof.

The directions of movementA of the various pistons are indicated byVthe; arrows` appearing thereon; similarly,V curvedarrows indicate vtheow of the working fluidilatthe. time indicated.

It will be noted that` four pistons of thegroup designated I5.` are. ontheir upwardV (intake) stroke. It. will also benoted that at` this time,the fluid is so. valvedby vthe adjacent piston of the other groupv ofpistons (l5)v that. iiuid is drawn from they lower manifold 24.

By referring to thoser pistons: .Ie which are on their downward stroke(delivery) it will be noted that the-iiuid displaced thereby isdischarged into the manifold 22. It will be noted that fourrof thepistons. I5 are. on their downwardv (intake) stroke and that v.theydrawuid from the same manifold 22 to .which the. pistolflsfY i6. delivertheir uid..

It will also be noted thatthose pistons I5 which are on their upward(delivery) stroke discharge their fluid into the manifold. 28.. From theabove it will be seen that the arrangement is such that a, two stagepump is provided. rihe pistons IB serve to raise the pressure of thefluid from, say, atmospheric to an, intermediate pres'- sure, from whichpressure fluid. is taken and the pressure thereof raisedl by means ofthe pistons .I 5 to approximately double the intermediate pressure.

The form of the invention` shown in Figs.. 7 to 10, inclusive, comprisesa 10 cylinderzpump of the single stage variety, in which the volume' ofthe pump may be varied through hydraulic pressure means. In this form ofconstruction, there are five pistons I5al, I5a2, I5av3, was, and 5a5which are received in cylinder bores in cylinder block IIa and vepistons IBai, IGaZ.. iSaS, laad, and i6a5 which operate in bores on theother end of the cylinder block, the pistons of the first group beinginterspersed .with lthose of the second group and each piston of eachgroup being formed with valve portions which serve to valve the adjacentcylinder of the other group.

Power for operating the pump is applied through the shaft I2a. which iscoaxial with. the stationary cylinder block I Ia. The blockv includes aplurality of sets of cylinder bores Isa and Illa within which thepistons a. and 16aare reciprocally mounted, respectively.

Annular housing 2Ia surrounds the cylinder block and is provided with aplurality of annular manifolds LI,HI, L2, and H2. LI and L2 are lowpressure manifolds and communicate with each other and with the suctionline L3 as indicated schematically at the top of Fig. 7 and in Figs Il).HI Yand Haare4 highpressure manifolds and communicate .with eachother-andv with4 they high pressure or delivery manifold line. H3.; Themanifold LI communicates through an annular port 25a, in the cylinderblock with the. valve chamber portions. 25a in cylinders Isa, cylinderheads 26a .being provided in. cach. cylinder Ida. for closing off suchcylinder' from the. port 25a, and providing pressure chambers 21a.vtherein. Y

The highpressure manifold H2 communicates through an.V annularA port25a. with the. valye chambers 29a of cylinders Ilia'. This port'isclosed off from theotherV cylinders. I3a bycylinder heads 32a which.provide4 pressure chambers 33mm, cyl,- inders |311.

High pressure manifold HIi communicates throughY a.. port 23a with thevalve chamber portionin cylinders. Isa only and low pressure manifold L2communicates through ports 3 I a .with the valvei chamber portion of.the cylinders.v Ma only.

The pistons are all formed with a. reduced sectionwhich serve asVpassages for connecting the various ports. at different times. and areformed withconnecting rod ends Ila. and Ida terminating in ball endsI'Ibi and lab respectively.

A- wobble disk 35a isarranged to reciprocate the pistons .i 5w while: aAsecond wobble disk 36a serves to reciprocate the other group. ofpistons ia. Each wobble diskis' supported on the pump shaft 52a forrotation therewith, andis angularly adjustable relative to. the. axis.of the. shaft to vary the piston stroke. Each wobble disk comprises ahub Szla pivoted on the pump shaft bya pin 38a, extending.l throughoutthee shaft andhub. Said hub has attached thereto. a wobble. plate 39awhich carries anouter Vring maand an annular plate Ma. Bearing againstthe inner face of wobble disk 39a. are. aplurality of shoes da, theshape of which canbest be seen in Fig. 8. One side of each of said shoesis formed vwith a spherical pocket fitting the ball IIb or Ii8b on the,pistons. The. other side of said'balls are contacted by a sphericalsurface formed on annular rings 43a' which `bear againstv and areslidable upon the plate dla. IThey plates 39a and 4ta are spaced bymeans of a ring Miu and are clamped inplace by the nut. @5a. A ring 45a.may also be provided, said ring being rctatatrle relative to ring ddd.and. received insuitable cut-away portions on the shoes 42a, and seatrings 43d. It will be noted that ifv the shaft I2ais2rotated with thewobble plates in the. position shown, the pistons will be reciprocatedin. their cylinder bores. and that the extent of reciprocation dependsupon the angular position of the wobble disk. To reduce friction andwear a lm of oil under pressure is preferably maintained. between thevballs and their seats and also. between the shoes and the wobble plateSia. This is preferably accomplished by forming the pistons .with axialbores 55m communicating through an opening Sla, in the shoe, whichcommunicates. with suitably formed.V grooves '52aiandf 53a in the flatsurface ofthe shoe 42a (Fig. 8").V The axialv bore 500. is interceptedby a vtransverse bore 54a which terminates in a groove 55a in the pistonrod. Formed on the outer surface ofthe cylinder block is a groove. 56a.to which oil isv delivered under pressure as'through nipple 51a. It willbe noted that when the piston is near the center of its stroke, apassage 58d will align with the groove 55a, thus allowing oil to flowthrough said various passages to the grooves 52 and 53a and also. to thespace between` the balls and their seats.V It will also be noted thatthe length of time per revolution will vary with the piston stroke. Whenthe pump is operated at a full stroke, the oil supply will be connectedto the lu bricating passages only a relatively small part of the time,whereas when the stroke is very small (when high pressures aredeveloped) the lubricating oil is almost constantly in communication.Whereas in the form shown in Figs. l to 6, the adjustment of the wobbledisks is effected by means of a sleeve surrounding the operating shaft,the present form accomplishes such adjustment by forming the shaft l2ahollow and providing Within said shaft an axially slidable member toperform this function. This member comprises an adjusting slide Glawhich has a slot 62a to receive the wobble disk journal pin 38a and itis also provided with two pins 63a which carry shoes 64a which areslidable within slots 65a in the shaft l2a. Said pins also carry shoes66a which operate in sloping slots 61a formed in the hub 5ta of thewobble disk. It will be seen, therefore, that axial movement of theadjusting slide 6 la, will cause the wobble disks to be moved abouttheir journal pins 38a and 33a due to the relative angles of the slots65a and Gla. The slots are so arranged that when the adjusting slide 6|ais moved fully to the left (Fig. 7) both wobble disks will stand at Zerovolume, viz: with the wobbley plates 35a at right angles to the pumpshaft I2a.

It would appear from Fig. '7 that journal pins 38a and 38a are located90 from each other. In an actual construction of such a l0 cylinderpump, the pins 38a and 38a are displaced only 54 from each other. of thepistons will be displaced 90 out of phase with the adjacent piston ofthe other set and, therefore, will be able to serve to valve the fluidmoved by such adjacent piston.

While the adjacent slide ila may be moved by hand or other means, it isoften desirable to provide hydraulic means for such adjustment. This isaccomplished in the present instance by forming the adjusting slide withan extension 64a whi-ch is connected through a ball bearing 'lila withthe piston 'lla fitted within a cylinder 12a. Connected to the left endof said cylinder is a port 13a and connected to the right part of saidcylinder is a port 14a. These ports lead to a valve cylinder 15a withinwhich is slidably mounted the piston valve member 16a preferably formedgenerally as shown. Ports 'lla and 18a lead from a conduit 19a which isconnected to a drain pipe leading to a sump. Oil under pressure is ledto the valve cylinder through a conduit Sca. It will be seen that if thevalve piston ita is moved to the right, oil under pressure will beadmitted from 80a. through 14a to the rear of the piston Ha causing itto move to the left and therefore reducing the stroke of the pump.During this time the discharge port la is opened to port Tia. Thisadjusting motion continues until the piston valve 16a, is restored toits central position. If it is now moved to the left the reverseoperation will occur, the piston l la will move to the right and thepump stroke will be increased. The operation of this form of pump willbe clear from a study of FigflO. The directions of movements of thevarious pistons are indicated by the arrows appearing thereon; similarlycurved arrows show the flow of the working fluid at the time indicated.

It will be noted that two pistons lal and |6055 of the one group are ontheir upward (intake) stroke. It will also be noted that, at this time,the fluid is so valved by the adjacent piston of the By this arrangementeach :n

other group of pistons that fluid is drawn from the intake manifold Ll.

By referring to those pistons |6a3 and I6a4 which are on their downardstroke (delivery) it will be noted that the fiuid displaced thereby isdischarged into the delivery manifold HI. It will be noted also thatpistons |5112 and l5a3 which are on their downward (intake) stroke areso valved by their adjacent pistons that they draw iuid from the intakemanifold L2 and that those pistons |5114 and |5a5 vwhich are on theirupward (delivery) stroke are so valved that they discharge fluid intothe delivery manifold H2.

As indicated in dotted lines in Figs. 7 and 10, the manifolds Hl and H2are connected together and to a common delivery manifold H3; similarlythe intake manifolds LI and L2 are connected together to a common intakeconduit L3. Thus all pistons draw fluid from a common intake and deliverto a common delivery conduit, thus providing a single stage pump.

It is to be noted that, if the manifolds Hl and H2 are not connectedtogether, it will be possible l to deliver two streams of fluid whichwill be equal in amount if the pistons are all of the same area, or in adifferent but definite proportion if the pistons of one group have adifferent area from those of the other group. It is also to be notedthat if the inlet manifolds Ll and L2 are not connected together and thedischarge manifolds Hl and H2 are not connected together, the pump maybe used to pump two independent streams of uid.

Furthermore, the device may be used as a flow divider by supplyingliquid under pressure to one pair of manifolds and by having the othermanifolds connected to independent circuits. In this event, no externalpower is applied to or taken from the drive shaft.

While the above description has referred to applicants illustrativeembodiments as a pump it is to be understood that it may also be used asan hydraulic motor by supplying to it liuid under pressure througheither the manifolds HI and H2 or Ll and L2.

It is intended that the patent shall cover, by suitable expression inthe appended claims, whatever features of patentable novelty exist inthe mechanism disclosed.

I claim:

l. An hydraulic unit of the positive displacement type comprising ashaft, a plurality of sets of cylinders, the cylinders of one set beinginterspersed with those of the other set, each cylinder having apressure chamber and a valve space, pistons reciprocable in saidcylinders, each 4piston being shaped to form a valve body movable in theassociated valve space, supply manifold means, delivery manifold means,valve passages connecting said manifold means with the pressure chamberof each cylinder through the valve space of an adjacent cylinder,whereby the piston in one cylinder of a set controls the valving of saidadjacent cylinder of another set, and means on said shaft forreciprocating the pistons in said adjacent cylinders substantially 90out of phase.

2. An hydraulic unit comprising a shaft, a pair of cylinders, eachhaving a pressure chamber and a valve space, pistons reciprocable insaid cylinders, each forming a valve body movable in the associatedvalve space, supply manifold means, delivery manifold means, -valvepassages connecting said manifold means 'with the pressure chamber ineach cylinder through the valve space in the other cylinder, whereby thepiston in each .cylinder controls the :valvii-igf-of the-otherlcylinder, and a separate wobble disk on ysaid shaft for :actuating.each of said-pistons.

43. An `hydraulic unit comprising a shaft, a pair of cylinders, Aeach:ha-vinga pressure cham- :berand a valve space, pistons reciprocable insaid cylinders, .eachforminga valve ibcdy movable in the .associatedvalve space, supply manifold means, delivery manifold means, valvepassages connectingsaid:manifold-means with the pressure chamberin eachcylinderlthrough the valve space .in the other cylinder, fwhereby the.piston in each cylinder controls the valving of the other cylinder,separate -Wobblefdisks cnsaid :shaft for ,actuating said pistons, andlmeans :for .supporting said wobble disks .on .said shaft -Lso as torecipro- .cate said pistons substantially .90 ,out of phase.

4. An hydraulicunit comprising fa shaft, a pair of cylinders, eachhaving arpressunechamber and a valve space, pistons :reciprocable insaid cylinders, each forming a valve bodymovableinthe associated valvespace, .supply :manifold means, .delivery manifold fmeans, valvepassages .connecting -said manifold imeans with the lpressure .chamberineach cylinder :through the valve space in the other cylinder, wherebythe piston in :each cylinder controls .the valving Vof the otherY.cylinder, separate wobble Adis-ks yonsaid shaft for `actuating saidpistons, Vmeansffor supporting said wobble disks on said shaftV so vasto.reciprocate said vpistons substantially .796 .out .of phase, :and meansfor simultaneously:adjusting theangles of said wobble vlplates forvanyi-ng fthe strokes of A:said pistons.

5. .An-hydraulic uni-t 4of. the positive Vdisplacement type comprisingasl-raft, separateg-roups of `axially extending cylinders, pistons inone group of cylinders .having .operating .meanslextending -in onedirection, pistons in .another Egroup of cylinders having operating:means extending .in the opposite direction reciprocable in saidcylinders, a single Adelivery manifold common to all cylinders, an inletmanifold communicating with the vcylinders associated with one group ofpistons, a

secondinlet manifold .communicating with Asaid other cylinders, separate`wobble disks-on said shaft ,for `reciprocating ,each group of pistons,Vand means for simultaneously adjusting .the angle of said wobble,disksfor varying thestrokes of said pistons. 4

6. An hydraulic unit .comprising .a shaft, a cylinder block having-.aplurality of axial cylinders, pistons reciprocable in said cylinders,alternate groups of pistons having:operating means extending in oppositedirections, means onsaid shaft for ,w

reciprocating the pistons having their roperating means extending in onedirection, separate means on said shaft for reciprocating the pistonshaving their operating means extending in the -op posite direction, andmechanismfor simultaneously adjusting said piston reciprocating means,to vary the 'strokes of said pistons of eachlgroup simultaneously. Y

'7. An Vhydraulic unit comprising a sham, .a cylinder block having aplurality of axial cylinders, pistons reciprocable in said cylinders,alternate groups of pistons having operating means extending in oppositedirections, means on said shaft for reciprocating the pistons havingtheir operating means extending in one direction, separate means on saidshaft for reciprocating the pistons having their operating meansextending in the opposite direction, and mechanism movablelongitudinally of said shaft for simultaneously adjusting said pistonreciprocating means,

vders, a wobble diskvfor reciprocatingsaid pistons,

and means for connecting said disk to said piston rod including `aslidably mounted crosshead in alignment with said rod, means looselyconnectingsaid rodt-osaid crosshead, and means for connecting said diskto said crosshead for reciprocationthereby.

:9. .An :hydraulic 4unit com-prising a relatively rotatable shaft `andcylinder block, a piston and `piston rod 'reciprocable in said block,means von fsa-id shaft for reciprocating said piston including .a wobbledisk, means for transmitting recipro- -catingfforces from said =disk Itosaid piston sub- `s'tantia'llywithout imposing side thrust on saidpiston, including a Vslidably mounted crosshead 5loosely connected tosaid piston rod, thrust mem- ?oers in said crosshead on opposite sidesof sa-id disk, means connecting one thrust member to said sleeve, saidother 'thrust member being adapted to engage the end-of -said pistonrod.

10. An hydraulic unit comprising a relatively rotatable shaft landcylinder block, a piston and piston rod reciprocable in said block,means on said shaft for reciprocating said piston including a wobbledisk, means for transmitting reciprocating forces `from said disk tosaid piston substantially Without imposing side thrust on said piston,including a slidably mounted crosshead loosely connected to said pistonrod, 'thrust members :in said crosshead on opposite sides of said disk,vhemispherical wear members movably mounted in said thrust member forengagement by vsaid disk, and means yieldingly connecting one 4thrustmember to said crosshead, said other thrust member being adapted to`vengage the end of said piston rod.

V1'1. An hydraulicunit comprising a relatively rotatable shaft andcylinder block, a pistonand piston rod reciprocable in said block, meanson lsaid 'shaft for reciprocatingv said piston including a wobble disk,means for transmitting reciprocating forces from saiddisk to said pistonsubstantially without imposing side thrust thereon, including acrosshead formed `by a slidably mounted sleeve loosely connected to saidpiston rod, thrust members mounted in said sleeve engaging oppositesides of said disk, and vmeans yieldingly connecting one. thrust memberto ysaid sleeve,said Vother thrust member Vbeing adapted to engage theend 'of said piston rod.

.12. The combination in an hydraulic unit having cylinders 'and pistons,of a shaft, a wobble disk for 'reciprocating said pistonsY including ahub surroundinggsaid shaft and pivoted thereon for angularIadjustment'relatively thereto, means for adjusting the angularyposition of Said hub including a grooved sleeve vslidably supported onsaid sha-ft and extending through said hub, a pin mountedV intliegrocn/e of said 'sleeve and connected to said hub whereby movementof said sleeve longitudinally of said shaft varies the angularadjustment of said wobble disk.

13. An hydraulic unit comprising a pair of cylinders, each having apressure chamber and a valve space, pistons reciprocable in saidcylinders, each piston forming a valve body movable in the associatedvalve space, a supply manifold, a delivery manifold, valve passagesconnecting at times said supply manifold with the pressure chamber inone of said cylinders, and, at other times, connecting the said pressurechamber with the delivery manifold, through the valve space in the othercylinder, whereby the piston in each cylinder controls the valving ofthe other cylinder, operating means for actuating said pistons in such amanner as to reciprocate said pistons substantially 90 out of phase.

14. An hydraulic unit comprising a plurality of pairs of cylinders, eachhaving a pressure chamber and a valve space, pistons reciprocable insaid cylinders, each piston forming a valve body movable in theassociated valve space, a supply manifold, a delivery manifold, valvepassages connecting at times said supply manifold with the pressurechamber in one of said cylinders of a pair, and, at other times,connecting the said pressure chamber with the delivery manifold, throughthe valve space in the other cylinder of said pair whereby the piston ineach cylinder of a pair controls the valving of the other cylinder ofsaid pair, operating means for actuating said pistons in such a manneras to reciprocate the pistons of a pair substantially 90 out of phase.

15. An hydraulic unit comprising a pair of cylinders, each having apressure chamber and a valve space, pistons reciprocable in saidcylinders, each piston forming a valve body movable in the associatedvalve space, a supply manifold and a delivery manifold for each cylinderof said pair, valve passages connecting at times said supply manifold ofone of said pair of cylinders Ywith the pressure chamber in one of saidcylinders, and, at other times, connecting the said pressure chamberwith the respective delivery manifold through theY valve space in theother cylinder, whereby the piston in each cylinder controls the valvingof the other cylinder, operating means for actuating said pistons insuch a manner as to reciprocate said pistons substantially'90" out ofphase.

16. An hydraulic unit comprising 'a power shaft, a cylinder, a pistonreciprocable in said cylinder, operating connections between said shaft4and said piston including a wobble plate and a shoe slidable on saidplate and operatively connected to said piston, and means for deliveringlubricant between said relatively slidable shoe and plate comprising asource of pressure for said lubricant, a duct leading therefrom to saidcylinder at a point always covered by said piston, a lubricant passagein said piston connecting at one end to the space between saidrelatively slidable shoe and wobble plate and connecting at the otherend to a transverse port in said piston so located that when the pistonis in substantially mid-position it aligns with said duct which connectsto the pressure source, the said duct and port being so dimensioned thatcommunication between them is interrupted eX- cept when the piston isnear mid-stroke.

17. An hydraulic unit comprising a power shaft, a cylinder, a pistonreciprocable in said cylinder, operating connections between said shaftand said piston including a wobble plate, a

shoe slidable on said plate, said shoe being formed with a sphericalseat in which a ball on said piston seats, and means for deliveringlubricant to the space between the plate and the shoe and between theball and its seat comprising a source of pressure for said lubricant, aduct leading therefrom to said cylinder at a point always covered bysaid piston, a lubricant passage in said piston connecting at one end tothe relatively slidable surfaces between the shoe and the plate andbetween the shoe and the ball and connecting at the other end to atransverse port in said piston so located that when the piston is insubstantially mid-position it aligns with said duct which connects tothe pressure source, the said duct and port being so dimensioned thatcommunication between them is interrupted except when the piston is nearmid-stroke.

18. An hydraulic unit comprising a power shaft, a cylinder, a pistonreciprocable in said cylinder, operating connections between said shaftand said piston including relatively slidable members and means fordelivering lubricant to said relatively slidable members comprising asource of pressure for said lubricant, a duct leading therefrom to saidcylinder at a point always covered by said piston, a lubricant passagein said piston connecting at one end to said relatively slidablesurfaces and connecting at the other end to a transverse port in saidpiston so located that when the piston is in substantially mid-positionit aligns with said duct which connects to the pressure source, the saidduct and port being so dimensioned that communication between them isinterrupted except when the piston is near mid-stroke.

19. An hydraulic unit comprising a power shaft, a cylinder, a pistonreciprocable in said cylinder, operating connections between said shaftand said piston including relatively slidable members and means fordelivering lubricantl to said relatively slidable members comprising asource of pressure for said lubricant, a duct leading therefrom to saidcylinder at a point always covered by said piston, a lubricant passagein said piston connecting at one end to said relatively slidablesurfaces and connecting at tHe other end to a transverse port in saidpiston so located that when the piston is in substantially mid-positionit aligns with said duct which connects to the pressure source.

ELIAS ORS-HANSKY, JR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 00 1,947,902` DeStoutZ Feb. 20,1934 1,971,601 Dilg Aug. 28, 1934 2,695,316 Davis Oct. 12, 19372,173,856 Orshansky Sept. 26, 1939 2,324,524 Mercier July 20, 1943

